DNA Extraction
To study DNA and learn how our
genes function, scientists must
be able to work with DNA itself,
outside the protective walls of
the nucleus and cell membrane.
So researchers have learned to
separate (to isolate or extract) DNA from the proteins and other
substances in the cell.
Kristin Darden, Janelle
Moran, Deb Semmler
Before we get into this, though,
let’s do a bit of review.
What is DNA?
Deoxyribonucleic Acid
That’s a mouthful. Rather than going
through a long drawn out explanation, try
this Tour of the Basics to refresh your
memory.
DNA is a hardy molecule, and one of the
largest known. To work with it, we need to
extract it from the other cellular materials.
Us old folks will
remember Oliver
Hardy.
Get it- Hardy? →
So what would you use the isolated
DNA for?
Extraction of DNA is often an early step in
many diagnostic processes used to detect
bacteria and viruses in the environment as
well as diagnosing disease and genetic
disorders.
That’s great, but I’m not a
geneticist. Why would I do this
process in my class?
‘Cuz DNA is cool to look at
with your students!
Okay, I’m listening- so what is DNA
Extraction?
Simply put, DNA
extraction is the
removal of
deoxyribonucleic acid
(DNA) from the cells
or viruses in which it
normally resides.
So how do I extract the DNA?
Start by breaking the cells open to expose
the DNA within.
Then remove the nuclear membrane lipids
by adding a detergent.
Finally precipitate the DNA with an alcohol.
This step will also remove alcohol-soluble
salts.
Yeah, right- want to run that by me
again?
It’s not as difficult as it sounds.
Any age student can do it- from kindergarten
to AP Biology students.
It doesn’t require any fancy laboratory
equipment, if you don’t have it.
You can make it as simple or as complex as
you’d like.
Watch this to see how simple it can
be.
strawberry extraction
Now obviously, that was a bit too simple for
your intermediate classes, so here’s
another video that gives you an idea for
that.
Kiwi extraction demo
WHERE DOES THIS FIT?
http://www.doe.in.gov/standards/core.html
State Standards
3rd Grade
3.1.2
3.1.3
3.1.4
3.1.5
3.2.2
3.2.4
3.2.6
5th Grade
5.1.1
5.1.2
5.1.3
5.2.4
5.2.7
5.4.1
5.4.2
5.4.3
Biology I
B.1.1
B.1.21
B.1.26
B.1.27
B.2.4
Resources for lessons plans,
tutorials, videos, labs
• Virtual DNA isolation lab – this is an excellent hands-on presentation
that can be used as an introduction or review of the DNA isolation
lab.
• DNA isolation lab – this is the lab we did in the preparation of our
DNA for gel electrophoresis. Copies of the PCR lab and gel
electrophoresis are also included.
• How to Extract DNA from Anything is a good choice if you would
want to make comparisons about the different amounts of DNA
formed from different organisms or you would like to vary some of
the reagents.
• Make Your Own DNA Necklace is a fun activity- you can even sell
them around Valentines Day as a fund raiser- i.e. “Why Give Candy
and Flowers- Give Your Loved One a Piece of Yourself”!
More Resources
• DNA Overview –explains what DNA is and
includes lots of additional information.
• NOVA – this Nova site has videos (good
for middle to high school age) and it
includes classroom activities, links to
books, case studies, etc.
• From the Beginning- from early
elementary to college, this site explains
pretty much anything you would want to
know about genetics.